Professor studying microbial physiology, specializing in prokaryotic development, developmental signaling, gene essentiality, and bacterial responses to microgravity
Research Interests
Research in my laboratory is centered around the model developmental bacterium Caulobacter crescentus. This organism produces two different cells, in shape and internal signaling state, after every division. This is achieved by a complex signaling network that coordinates activities all throughout the cell cycle. Our work aims to untangle this network and explore how it has evolved in related organisms. We are also focused on the complex regulation and localization of the pilus, a structure very important to cellular adhesion, whose regulation is strictly timed within the cell cycle. Our studies of how these systems evolve between organisms lead to in-depth exploration of gene essentiality, which itself led to investigating bacterial responses to microgravity, which involved culturing bacterial samples aboard the International Space Station. In the future we hope to engineer bacteria to better help plants grow in space.
Biography
A native of the Chicago suburbs, I obtained my bachelors degree at Purdue University. I followed that with my PhD in Microbiology at the University of Georgia and performed postdoctoral research at Indiana University prior to joining the faculty here in 2012. Avid gamer, amateur cook, and all around nerd.
Publications
In microgravity, bacteria undergo intriguing physiological adaptations. There have been few attempts to assess global bacterial physiological responses to microgravity, with most studies only focusing on a handful of individual systems. This study assessed the fitness of each gene in the genome of the aromatic compound-degrading Alphaproteobacterium Novosphingobium aromaticavorans during growth in spaceflight. This was accomplished using Comparative TnSeq, which involves culturing the same saturating transposon mutagenized library under two different conditions. To assess gene fitness, a novel comparative TnSeq analytical tool was developed, named TnDivA, that is particularly useful in leveraging biological replicates. In this approach, transposon diversity is represented numerically using a modified Shannon diversity index, which was then converted into effective transposon density. This transformation accounts for variability in read distribution between samples, such as cases where reads were dominated by only a few transposon inserts. Effective density values were analyzed using multiple statistical methods, including log2-fold change, least-squares regression analysis, and Welch’s t-test. The results obtained across applied statistical methods show a difference in the number of significant genes identified. However, the functional categories of genes important to growth in microgravity showed similar patterns. Lipid metabolism and transport, energy production, transcription, translation, and secondary metabolite biosynthesis and transport were shown to have high fitness during spaceflight. This suggests that core metabolic processes, including lipid and secondary metabolism, play an important role adapting to stress and promoting growth in microgravity.
Courses Taught
- BISC 333 General Microbiology
- BISC 438 Microbial Physiology
- BISC 614 Advanced General Microbiology
- BISC 675 Advanced Microbial Physiology
- BISC 637 Prokaryotic Development
Education
B.S. Microbiology, Purdue University Main Campus (2001)
Ph.D. Microbiology, University of Georgia (2007)